Sound recording and reproducing device.



-No. 704,047. Patented July 3, I902.

E. R. JOHNSON. SOUND RECORDING AND REPRDDUDING DEVICE.

(Application flied Nov. 2, 1900.)

(No Modal.)

UNITED STATES.

PATENT @FFICE.

ELDRIDGE R. JOHNSON, OF PHILADELPHIA, PENNSYLVANIA.

SOUND RECORDING AND REPRODUCING DEVICE.

SPECIFICATION forming part of Letters Patent No.- 704,047, dated July 8,1902. Application filed November 2, 1900- Serial No. 35,193. (No model.)

To all whom, it may concern.-

Be it known that I, ELDRIDGE R. JOHNSON, a citizen of the United States,and a resident of the city of Philadelphia, State of Pennsyl- Vania,have invented certain new and useful Improvements in Sound Recording andReproducing Machines, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings, formingpart of this specification.-

My invention relates to certain improvements in sound recording andreproducing apparatus, and particularly to that part known as thesound-box.

In recording sound-Waves I have found from experience that thestylus-point must be adjusted to a nicety, even down to a thousandth ofan inch, in order to obtain the very best results, and I also find thatunder different conditions of temperature this adjustment varies byreason of the contraction and expansion of the various parts of thedevice. Consequently Ihave found it necessary to provide for very finelyadjusting the stylus-point and its supporting-bar and to provide atensioning device therefor.

The principal object of this invention is to provide a sound-boxparticularly adapted for recording purposes so constructed as to readilyyield to the impulses of the sound-Waves in any and all directions;also, in providing means for finely adjusting the stylus-point, so thatthe depth of the cut may be regulated to a nicety; also, in providing atensioning device which will maintain the proper adj ustment of thestylus-bar under different conditions of temperaturein the event ofcontraction or expansion.

With these and other objects in view my invention consists in theconstruction and arrangement of the mechanism, substantially ashereinafter set forth, and particularly pointed out in the claims.

Referring to the accompanying drawings, Figure 1 is a perspective viewof a recording sound-box embodying my invention. Fig. 2 is a centralsectional elevation through the same. Fig. 3 is a detail perspectiveview of the stylus-bar. Fig. 4 is a detail section illustrating one ofthe studs for supporting the stylus-bar and also illustrating theknifeedge bearing.

the Serial No. 2,178.

In the said drawings I provide a circular supporting-disk A, which hasformed thereon or secured thereto the usual tubular section a, adaptedto be connected either directly or indirectly to a mouthpiece or othersound-conveying device. The inner end of the tubular section a projectsa short distance beyond the front face of the disk A, as illustrated inFig. 2 of the drawings. Projecting from the front face of the section Ais a pin or rod b, the said rod being riveted or otherwise secured inthe section A.

B designates the diaphragm-holding section and consists of a circulardisk of a diameter corresponding to that of the, disk A, having itscentral portion cut out in the manner illustrated in Fig. 2 of thedrawings for the reception of the diaphragm O. Thefront portion 0 of thediaphragm-chamber is larger in diameter than the rear portion 0, andbetween these two portions is formed an inclined Wall 0*. The projectingend a of the tubular section a fits into the opening 0 formed in therear of the section B, the said opening being of slightlylarger diameterthan that of the tubular section, so as to allow of a slight playbetween these two parts. The section B is pivotally mounted on the rod1), carried by the disk A, so that the said section B may swing veryslightly, if desired. On the front face of the section B, I provide acircular plate D. The diaphragm C is supported by means of a liquid filmO, which adheres to the inner walls of the section B and also to anadjustable ring 0 the object of the said ring 0 being. to provide anenlarged surface adjacent to the diaphragm for the liquid film to adhereto, so that an increased body of liquid may be maintained and supportedby capillary attraction, this particular construction of diaphragm beingspecifically described in my application for patent filed January 20,1900, and bearing Secured to the center of the diaphragm Oby means ofthe usual wax or cement is a very thin rod e, which extends out beyondthe front plate D through the opening 01 provided therein and hassecured to its free end the arm f of the stylusbar F. This stylus-bar Fis substantially T-shaped in form, having a step or shoulder f in itscenter at the point where the arm f is secured to thehorizontallydisposed arms f and f The arm f is bent downwardly at itsend to form a shank, to which is secured the stylus-point g. On theupper surface of arm f I provide the knifeedge bearing h, which isadapted to bear against a V-shaped notch h, formed on the under side ofthe stud M, which is secured in the plate D of the sound-box frame.

On the under surface of the arm f of the stylus-bar F, I provide aknife-edge bearing 1', located at or near the end of said bar, which isadapted to a V-shaped notch 71', provided in the upper surface of thestud '6 which stud is also secured to the plate D of the soundbox frame.A small groove or notch j is provided on the end of the arm f and asmall openingj is formed on the downwardly-extending portion of the armf a short distance below the knife-edge hearing it. Secured to the arm fa short distance above its connection with the horizontal arms f f 3 isa cord G, preferably composed of silk, the said cord passing over theend of the arm f resting in the groove j, passing around the under sideof the stud 2' and through the opening j, formed in thedownwardlyextending section of the arm f From thence it passes upwardly,bearing slightly against the stud 71. and is connected at a point abovethe center of the diaphragm to a finely-tensioned coil-spring H. Securedto the upper face of the plate D of the sound-box frame is asubstantially horizontally disposed arm L, the said arm being adjustably mounted to the sound-box frame by means of the pivot-screw l. Tothe free end of the arm L is secured the upper end of the coiled springH, to the lower end of which is secured one end of the cord G, asheretofore described. It will thus be seen that the stylus-bar F isyieldingly supported by means of the silk cord G under the tension ofthe spring H and that this spring will serve to keep the knife-edgebearings always in contact with the notches provided in the studs 713?,and thus take up any looseness or defect which might be caused by reasonof the expansion and contraction of the various parts. It will also bereadily seen and understood that the tension may be increased ordiminished by adjusting the setscrew Z and regulating the height of thearm L. By reason of the sound-box section B being pivotally mounted onthe rod I) also allows this section to slightly expand or contract, asthe opening 0' is slightly larger than the projecting end a of thetubular section a.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

1. In asound-recordingapparatus,the combination with the sound-box framehaving a diaphragm located therein, of a horizontallydisposed stylus-barhaving an arm perpendicularly disposed and connected with the diaphragm,knife-edge hearings on the under side of the horizontally-disposed barat one end and on the upper side at the opposite end, and means formaintaining the said stylus-bar in contact with its bearings, for thepurpose described.

2. In a sound-recording apparatus,the'com bination with the sound-boxframe, of a diadiaphragm, knife-edge bearings located ateach end of thestylus-bar on its upper and lower sides respectively, studs carried bythe sound-box frame against which the knifeedges bear, and a cordsecured to the central arm of the stylus-bar bearing against one end ofthe horizontal bar and passing under its supporting-stud and through anopening provided in the opposite end of the same, the

end of said cord being yieldingly secured to the sound-box frame,substantially as described.

4. In a sound recording and reproducing apparatus, the combination withthe sound box frame, of a diaphragm, a horizontallydisposed stylus-bar,a central arm for said bar having a connection with the diaphragm, studsarranged below one end and above the other end of the stylus-bar,knife-edges adapted to bear against the said, studs, a cord secured tothe stylus-bar and. passing under each of its bearings, a spring securedto the other end of said cord and means for adjusting the tension ofsaid spring, substantially as described.

5. The combination with the sound-box frame, of a diaphragm locatedtherein, a T- shaped stylus-bar having its vertical arm secured to thediaphragm, a pair of studs secured to the sound-box frame, extendingunder the stylus-bar at one end and above the same at the other end,V-shaped notches formed in said studs, knife-edges carried by the lowerside of the bar at one end and the upper side at the opposite end, acordsecured to the stylus-bar and passing under each of its bearings forkeeping the said bearings in contact with the studs, a yielding springconnecting the end of the cord, and an adj ustable arm secured to thesound-box to which the free end of the spring is connected,

substantially as described.

6. The combination with the sound-box casing, of a diaphragm locatedtherein, a T- shaped stylus-bar having its vertical arm connected to thediaphragm, a stud, t extending under one end of the stylus-bar, aknifeedge carried by the lower side of the sty1usto the upper end of thecord, an arm, L, carbar adapted to a V-shaped groove in the stud, riedby the sound-box frame supporting the a stud, h located above the otherend of the coiled spring at its free end, and a set-screw,

stylus-arm, a knife-edge carried by the upper Z, for adjusting the saidarln, substantially as I 5 5 side of the stylus-bar adapted to aV-shaped described.

groove provided in the stud, a cord, G, se- In witness whereof I havehereunto set my cured to the stylus-bar passing over the end hand this3d day of August, A. D. 1900. of same and under the stud, 5 said cordpass- ELDRIDGE R. JOHNSON; ing through an eye formed in the oppositeWitnesses:

[0 end of the stylus-bar and passing upwardly JNO. T. CROSS,

against the stud, if, a coiled spring secured LEWIS H. VAN DUSEN.

